diff --git a/composer.json b/composer.json
index b5cf6f5..2f10f5c 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
         "symfony/config": "~2.3|~3.0",
         "symfony/dependency-injection": "~2.3|~3.0",
         "symfony/filesystem": "~2.3|~3.0",
-        "symfony/yaml": "~2.3|~3.0",
+        "symfony/yaml": "~4.0",
         "twig/twig": "~1.16",
         "jakoch/phantomjs-installer": "2.1.1-p08"
     },